DR. KAY SCARPETTA, who keeps US coming back to Patricia Cornwell's sprawling crime novels, is one tough broad. As chief medical examiner for the state of Massachusetts, she has no trouble dealing with the gory sights and smells of dead bodies and violent crimes. "A select few of us come into this world not bothered by gruesomeness," she says. "In fact we're drawn to it, fascinated, intrigued." What she can't handle are threats to the person she loves best in the world, her brilliant, prickly niece, Lucy. In DEPRAVED HEART (Morrow/ HarperCollins, $28.99), Scarpetta is on the scene at the "accidental" death of a movie mogul's daughter when she receives a disturbing surveillance video shot in 1997 by Carrie Grethen, Lucy's mentor (and first love) at the F.B.I. Academy in Quantico, Va. Because it suggests that Lucy was in possession of an illegal firearm, Scarpetta worries herself sick that Carrie, a malicious psychopath, will use the clip to undermine her niece's career. But for fuzzy reasons, Scarpetta keeps her worries to herself, unwilling to share them with her husband, an F.B.I. profiler, or her cop friend, Pete Marino. Not even when the F.B.I. comes down on Lucy. Once Scarpetta decides to ferret out Lucy's secrets, the novel becomes more of a psychological thriller than a crime drama, although that suspicious death isn't entirely forgotten. Scarpetta follows the autopsy on her computer screen and even wades into the murky waters of "invisibility technology," hoping to learn how "augmented reality or optical camouflage" might have figured in the case. But the real focus is on Scarpetta's obsession with Carrie: "For years she'd invaded my psyche I waited for her to torture and murder someone- I constantly looked for her when I was with Lucy and when I wasn't. Then I stopped." And then she started again. CHARLES FINCH'S VICTORIAN whodunits, with their resolutely aristocratic sensibility, can be a guilty pleasure for the more plebeian reader. His gentleman sleuth, Charles Lenox, is a partner in a London detective agency, but he's also the brother of a baronet and is married to the daughter of an earl. In HOME BY NIGHTFALL (Minotaur, $25.99), a sterling addition to this well-polished series, all of London is talking about the renowned German pianist who disappeared from his dressing room after a concert. But before Lenox can apply his wits to that locked-room puzzle, he must head to the family estate in Sussex, hoping to console his grief-stricken brother after the sudden death of his wife. A series of odd, mysterious thefts in the nearby town of Markethouse prove the perfect distraction for Sir Edmund Lenox, as well as a chance for Finch to dazzle us with his amusing studies of country folk and his offbeat approach to historical particulars. So while we're treated to all the showy details of an elaborate ball at an ancestral manor, we're also beguiled by tidbits about the importance in Victorian society of wearing a hat and the remarkable contributions of the era's fanatical amateur geologists to the field of natural science. OUTSIDE of a Marvel comic book, can a crime story have too many heroes - even if they're all great guys? Absolutely, and Robert Crais's latest novel, THE PROMISE (Putnam, $27.95), is a case in point. His go-to protagonist, the California private eye Elvis Cole, is first on the job when an executive at a company that manufactures the chemical ingredients for heavy explosives hires him to find its top engineer, a woman who has gone looking for answers after her son was killed in a terrorist bombing. You don't want to fool around with chemical weaponry, international terrorists or a vengeful mother, so Cole recruits his scary friend, Joe Pike, a soldier of fortune who brings along his own scary friend, a "professional warrior" named Jon Stone. These big boys do so much heavy lifting that we almost lose sight of two other heroes, first met in Crais's previous book, the K-9 officer Scott James and his partner, Maggie, a German shepherd with more personality than all of them put together. THE KELLERMANS ARE on the march. In THE THEORY OF DEATH (Morrow/HarperCollins, $26.99), Faye Kellerman writes with her usual sensitivity about troubled teenagers and young adults like Eli Wolf, a math genius whose naked body is found in the woods not far from his college in Greenbury, N.Y. Detective Peter Decker, who relocated to this upstate burg after a more eventful career as a Los Angeles cop, is too conscientious to write off Eli's lonely death as a suicide, but when he opens an investigation it lands him in the snake pit of academic politics. Writing to her strengths, Kellerman shows her customary compassion for isolated souls like Eli and social outliers like his Mennonite farm family. Kellerman's husband, Jonathan, and their son, Jesse, team up in THE GOLEM OF PARIS (Putnam, $27.95) on something truly off the wall - a classically constructed detective story featuring the tormented hero of a previous book ("The Golem of Hollywood") that morphs into a supernatural thriller combining elements of Jewish legend, religious mysticism and pagan mythology. While the novel's paranormal elements don't mesh easily with the procedural work, it's hard to resist a protagonist who does battle with demonic giants and is in thrall to a woman who's part angel and part bug.